chuong 1_in

8/2/2019 chuong 1_in

1/36

Bi ging Thit K Kim Sot Cht Thi Rn

Phn m u:Cht thi rn(CTR) xut hin t khi con ngi c mt trn tri t. Con ngi

khai thc v s dng cc ngun ti nguyn trn tri t phc v cho i sng ca

mnh, ng thi thi ra CTR. Khi , s thi b cc cht thi t hot ng cacon ngi

khng gy ra cc vn nhim mi trng trm trng do s lng dn c cn thp.

ng thi, din tch t t nhin cn rng ln, nn kh nng ng ho CTR tt, do

khng gy tn hi n mi trng.

Khi x hi pht trin, con ngi sng tp hp thnh cc nhm, b lc, cm dn c,

th s tch ly CTR tr thnh mt trong nhng vn nghim trng i vi cuc sng

ca con ngi. Trong x hi cng nghip ngy nay, qu trnh pht sinh CTR gn lin vi

qu trnh sn xut, mi giai on ca qu trnh sn xut u to ra CTR, t khu khaithc, tuyn chn nguyn liu n khi to ra sn phm phc v ngi tiu dng. Sn phm

sau khi s dng c th ti sinh, ti ch hoc b, v cng l CTR. V th khi lng

CTR hin nay pht sinh rt ln, cng thm vo l s CTR cha c x l a vn

v CTR l 1 trong vn quan tm trong vic bo v mi trng trn ton th gii

Hnh 1.1 Dng vt liu v qu trnh pht sinh cht thi rn trong x hi cng

nghip(Ngun Qun l v x l cht thi rn Nguyn Vn Phc)

Thc phm tha v cc loi CTR khc b thi b ba bi khp ni trong cc th

trn, trn cc ng ph, trc l giao thng, cc khu t trng vv to mi trngthun li cho s sinh sn v phttrin ca cc loi gm nhm nh chut. Cc loi gm

nhm l im ta cho cc sinh vt k sinh nh b cht sinh sng v pht trin. Chng l

Vt Liu Th

Sn Xut

Ti ch v tisinh

Sn xut th cp

Ngi Tiu Dng

Thi b

Cht Thi

Cht Thi


2/36


nguyn nhn gy nn bnh dch hch. Do khng c k hoch qun l nn cc mm bnh

pht sinh t CTR lan truyn trm trng Chu u vo gia th k 14. Mi n th k

19, vic kim sot dch bnh nhm bo v sc khe cng ng mi c quan tm.

Ngi ta nhn thy rng CTR, nh thc phm tha phi c thu gom v tiu hy hp v

sinh th mi c th kim sot cc laigm nhm, rui, mui cng nh nguy c truynbnh.

Mi quan h gia sc khe cng ng vi vic lu tr, thu gom v vn chuyn cc

CTR khng hp l th hin r rng. C nhiu bng chng cho thy cc bi rc khng

hp v sinh, cc cn nh chut, cc ni cha thc phm tha l mi trng thun li

cho chut, rui, mui v cc vi sinh vt truyn bnh sinh sn, pht trin.

Thc t cho thy, vic qun l CTR khng hp l l mt trong nhng nguyn nhn

chnh gy nhim mi trng (t, nc, khng kh). V d: cc bi rc khng hp v

sinh gy nhim bn cc ngun nc mt, nc ngm v gy nhim khng kh (mi

hi). Kt qu nghin cu khoa hc trn th gii cho thy gn 22 cn bnh ca con ngi

pht sinh do mi trng b nhim l kt qu ca vic qun l x l CTR khng hp l.

Cc phng php ph bin nht c s dng x l CTR t u th k 20 l:

Thi b trn cc khu t trng. Thi b vo mi trng nc (sng, h, bin) Chn lp Gim thiu v t

Vn qun l CTR Vit Nam

Vit Nam, tuy dn s th ch mi chim hn 20% dn s ca c nc nhng

do c s h tng k thut qu km li t c chm sc nn tnh trng v sinh mi trng

b sa st nghim trng. Tnh hnh ng rc do thiu cc trang thit b k thut cn thit

v hiu ququn l mi trng km ang gy tr ngi cho s pht trin kinh t trong

nc v chnh sch m ca kinh t vi nc ngoi.

Qu trnh th ha Vit Nam trong nhng thp k trc y pht trin chm

vi t l th ha thuc loi thp nht so vi cc nc trong khu vc, t khi chuyn

sang nn kinh t th trng c s qun l ca nh nc , tc th ha ang c

tng nhanh hn. S gia tng dn s th trong khi cha c iu kin chun b tt v c

s vt cht gy nn nhiu hu qu v kinh t, xhi nghim trng. Kt cu h tng c sca cc th nh cp nc , thot nc , nh , giao thng th, v sinh mi trng

v.v cn yu km khng p ng c nhu cu ngy cng tng ca x hi.


3/36


Theo Bo co Din bin Mi trng Vit Nam nm 2004 ca World Bank, lng

cht thi pht sinh ti Vit Nam c tnh khong 15 triu tn/nm. Trong thp k ti,

tng lng CTR pht sinh c d bo s tip tc tng nhanh. Cc khu vc th chim

khong 24% dn s c nc nhng li chim hn 50% tng lng cht thi pht sinh, v

c tnh trong nhng nm ti, lng cht thi sinh hot pht sinh khong 60%, trong khicht thi cng nghip s tng 50% v cht thi c hi s tng gp 3 ln sovi hin nay.

Thnh ph H Ch Minh c din tch 2093,7 km2, dn s 6.117.251 ngi (thng

10/2004) phn b ti 24 qun huyn; ni tp trung 12 khu cng nghip, 2 khu ch xut v

1 khu cng ngh cao vi hn 800 nh my ring l, 15.000 c s sn xut va v nh, 62

bnh vin, hn 400 trung tm chuyn khoa, trung tm y t v hn800 phng khm t

nhn..., hin ang pht thi mi ngy khong 5.000 5.200 tn CTR th (bao gm

CTR sinh hot trong cc c s cng nghip v cht thi cng nghip khng nguy hi),

7001.100 tn cht thi xy dng, hn 1000 tn CTR cng nghip, trong 120 150

tn CTR nguy hi, 9 12 tn CTR y t.

Ti cc vng nng thn, cc ph thi ca sn xut nng, lm, ng nghip truyn

thng (nh thn l cy, rm r, v ht, phn gia sc...) hu ht c s dng un nu,

lm phn bn hoc chn lp. Nhng cht thi c ngun gc cng nghip, nh cht do,

nha, kim loi, d lng ho cht kh phn hy, tuy cha tr thnh vn bc xcnhng ang c xu hng tng ln nhanh chng.

Ti cc th v khu cng nghip, vic thu gom v x l CTR sinh hot, CTR

cng nghip, cht thi nguy hi ang l vn mi trng cp bch. Hin nay, Vit

Nam, nng lc thu gom CTR tt c cc th v khu cng nghip mi ch t khong

20 40%. Rc thi cha phn loi ti ngun, c thu gom ln ln v vn chuyn n

bi chn lp. Cng vic thu nht v phn loi cc ph thi c kh nng ti ch, hon ton

do nhng ngi ngho sinh sng bng ngh bi rc thc hin.

Vic ng dng cc cng ngh ti ch CTR ti s dng cn rt hn ch, cha

c t chc v quy hoch pht trin. Cc c s ti ch rc thi c quy m nh, cng

ngh lc hu, hiu qu ti ch cn thp v qu trnh hot ng cng gy nhim mi

trng. Hin ch c mt phn nh rc thi (khong 1,5 -5% tng lng rc thi) c ch

bin thnh phn bn vi sinh v cht mn vi cng ngh hp v sinh. Bin php x l

CTR hin nay ch yu l chn lp, nhng cha c bi chn lp CTR no t tiu chun

k thut v sinh mi trng. Cc bi chn lp CTR vn cn gy nhim mi trng t,

nc v khng kh do qu trnh vn hnh bi chn lp cn bt cp, vic x l nc r rc,


4/36


mi, v sinh mi trng km nh . Hn na hin nay qu t dnh cho cc bi chn lp

gn nh l khng c hoc khng .

Vn qun l cht thi rn Vit Nam l vn cn mi m v vy h thng

lut, cc vn bn qun l CTR cn hn ch cha theo kp vi s pht sinh CTR chng

mt nh hin nay. Hiu lc thi hnh cc vn bn quy phm php lut cn cha hiu qu.Nng lc th ch v ngun lc thc thi khung chnh sch ca Vit Nam hin ang

thiu cc cp tc nghip, v cc vn bn quy phm php lut cn cha c cng ch

thi hnh hiu qu. Cc quy nh i vi cc c s qun l cht thi, cc c s cng

nghip, cc bnh vin do B Ti nguyn v Mi trng v cc c quan b/ngnh khc

(B Y t, B Cng nghip, Cc ban qun l khu cng nghip) ban hnh cn cha c

cng ch thc thi y v cha gim st c vic thc hin hot ng qun l cht

thi do thiu nhn lc, phn cng chc nng nhim v khng r rng, vai tr ca cc c

quan chnh ph cn b chng cho v cn manh mn, hn ch trong vic iu phi gia

cc c quan. Do vy, dn n tnh trng thiu cc c ch khuyn khch i vi vic vn

hnh ng k thut cc bi chn lp, cc c s cng nghip u t cho cc h thng x l

chtthi v v th to iu kin cho vic p dng cc phng php tiu hu cht thi

r tin, khng an ton nh l thi cc bi rc l thin.

Nhn thc ca cng ng v bo v mi trng v an ton sc khe lin quan ticng tc thu gom, x l v qun l CTR vn cn ang trnh thp. Vic b ba bi

CTR xung cc knh rch gy mt v sinh, e da nghim trng n nguy c suy thoi

mi trng nc ngm.Cn tng cng cng tc truyn thng, gio dc trong cc bc

hc v vai tr ca qun l CTR trong x hi

Chin lc quc gia v qun l cht thi rn

Mc tiu ca Chnh ph l phn u ti nm 2050, tt c cc loi cht thi rn

pht sinh u c thu gom, ti s dng, ti ch v x l trit bng nhng cng ngh

tin tin, thn thin vi mi trng v hn ch khi lng cht thi rn phi chn lp n

mc thp nht. thc hin mc tiu ny, ngy 17/12/2009, Th tng Chnh ph

ban hnh Quyt nh 2149/Q-TTg ph duyt Chin lc quc gia v qun l tng hp

cht thi rn n nm 2025, tm nhn n nm 2050 c vi quan im qun l tng

hp cht thi rn l trch nhim chung ca ton x hi

Theo , vic qun l cht thi rn s thc hin nguyn tc "ngi gy nhim

phi tr tin". C th, qun l cht thi rn phi c thc hin theo phng thc tng

hp, nhm phng nga, gim thiu pht sinh cht thi ti ngun l nhim v u tin hng


5/36


u, tng cng ti s dng, ti ch gim khi lng cht thi phi chn lp. T chc,

c nhn pht sinh cht thi, gy nhim, suy thoi mi trng c trch nhim ng gp

kinh ph, khc phc, bi thng thit hi.

Chin lc cng t ra mc tiu n nm 2025, 100% cc th c cng trnh ti

ch cht thi rn thc hin phn loi ti h gia nh; 100% tng lng cht thi rn sinhhot th, 100% tng lng cht thi rn cng nghip khng nguy hi v nguy hi, 90%

tng lng cht thi rn xy dng th v 90% lng cht thi rn pht sinh ti cc

im dn c nng thn c thu gom v x l m bo mi trng. Lng ti nilon s

dng ti cc siu th v trung tm thng mi s gim 85% so vi nm 2010. Gii php

quan trng t c cc mc tiu trn l phi phng nga v gim thiu pht sinh cht

thi rn; thc y phn loi cht thi rn ti ngun; y mnh thu gom v vn chuyn

cht thi rn; tng cng ti s dng, ti ch cht thi...

c quy hoch chin lc nhm qun l cht thi rn, Chnh ph ch o s lp

v thc hin quy hoch xy dng khu lin hp x l cht thi rn cho cc vng kinh t

ca c nc. Tt c cc tnh, thnh ph trong c nc s lp v thc hin quy hoch qun

l cht thi rn; trong , xy dng v thc hin quy hoch xy dng khu x l cht thi

rn ti tn phng, x. ng thi, xy dng cc gii php v hon thin h thng vn bn

php lut v c ch chnh sch v qun l cht thi rn; thit lp c s d liu v h thngquan trc d liu v cht thi rn ton quc; thc y nghin cu khoa hc v mt bin

php ht sc quan trng l tuyn truyn, gio dc nng cao nhn thc cng ng v bo

v mi trng. Xy dng v thc hin cc chin dch truyn thng nng cao nhn thc

cng ng, khuyn khch tham gia vo cc hot ng phn loi ti ngun, gim thiu, ti

ch ti s dng cht thi rn, hn ch s dng ti nilon, khng rc ba bi...

a gio dc mi trng vo cc cp hc; thc hin cc hot ng th im, cc

sng kin gip qun l cht thi rn tt hn. Theo k hoch, t nay n nm 2025 s c

10 chng trnh thc hin chin lc quc gia v qun l tng hp cht thi rn c

hon thnh. Qu ti ch cht thi rn cng s c thnh lp nhm h tr cho cc hot

ng gim thiu v ti ch cht thi rn. ng thi, huy ng mi ngun vn u t cho

cng tc qun l cht thi rn, tm kim h tr t cc ngun vn ODA...


6/36


CHNG 1.

KHI QUT CHUNG V CHT THI RN

1.1 S b ngun pht sinh cht thi rn

Trong Ngh nh ca Chnh ph v qun l cht thi rn s 59/2007/N -CP nu

rcht thi rn l cht thi th rn, c thi ra t qu trnh sn xut,kinh doanh, dch

v, sinh hot hoc cc hot ng khc. Cht thi rn baogm cht thi rn thng thng

v cht thi rn nguy hi.

Cht thi rn pht sinh t nhiu ngun khc nhau, cn c vo c im cht thi

c th phn chia thnh 3 nhm ln: Cht thi th, cng nghip v cht thi nguy hi.

Ngun thi carc thi th rt kh qun l ti cc ni t trng (open area), bi v ti

cc v tr ny s pht sinh cc ngun cht thi l mt qu trnh pht tn.

Cht thi nguy hi thng pht sinh ti cc khu cng nghip, do nhng thng

tin v ngun gc pht sinh v c tnh cc cht thi nguy hi ca cc loi hnh cng

nghip khc nhau l rt cn thit. Cc hin tng nh chy trn, r r cc loi ho cht

cn phi c bit ch , bi v chi ph thu gom v x l cc cht thi nguy hi b chy

trn rt ton km. V d, cht thi nguy hi b hp ph bi cc vt liu d ngm nc nh

rm r, v dung dch ho cht b thm vo trong t th phi o bi t x l. Lcny, cc cht thi nguy hi bao gm cc thnh phn cht lng chy trn, cht hp ph

(rm, r), v c t b nhim.

Ngun pht sinh cht thi rn nh sau:

- T khu dn c:Bao gm cc khu dn c tp trung, nhng h dn c tchri. Ngun rc thi ch yu l: thc phm d tha, thu tinh, g, nha, cao su,... cn

c mt s cht thi nguy hi

- T cc ng thng mi:Quy hng, nh hng, ch, vn phng c quan,khch sn,...Cc ngun thi c thnh phn tng t nh i vi cc khu dn c (thc

phm, giy, catton,..)

- Cc c quan, cng s: Trng hc, bnh vin, cc c quan hnh chnh:lng rc thi tng t nh i vi rc thi dn c v cc hot ng thng mi

nhng khi lng t hn.


7/36


- T xy dng:Xy dng mi nh ca, cu cng, sa cha ng x, d bcc cng trnh c. Cht thi mang c trng ring trong xy dng: st thp vn, gch

v, cc si, b tng, cc vi va, xi mng, cc dng c khng dng na

- Dch v cng cng ca cc th: V sinh ng x, pht quan, chnh tucc cng vin, bi bin v cc hot ng khc,... Rc thi bao gm c rc, rc thi t

vic trang tr ng ph.

- Cc qu trnhx l nc thi: T qu trnh x l nc thi, nc rc, ccqu trnh x l trong cng nghip. Ngun thi l bn, lm phn compost,...

- T cc hot ng sn xut cng nghip:Bao gm cht thi pht sinh tcc hot ng sn xut cng nghip v tiu th cng, qu trnh t nhin liu, bao b

ng gi sn phm,... Ngun cht thi bao gm mt phn t sinh hot ca nhn vin

lm vic.

- T cc hot ng sn xut nng nghip:Ngun cht thi ch yu t cccnh ng sau ma v, cc trang tri, cc vn cy,... Rc thi ch yu thc phm d

tha, phn gia sc, rc nng nghip, cc cht thi ra t trng trt, t qu trnh thu

hoch sn phm, ch bin cc sn phm nng nghip.

Ngun gc ban u ca cht thi rn (CTR): sn phm hng ha v cc ph phmt vt liu rn.

Ngun cht thi rn th cp: chu trnh sinh trng v phn r t nhin ca thc

vt, chim mt t l nht nh trong dng cht thi.

CTR th c c trng bi cc sn phm tng i nh, s lng ln, v

vng i c ch ngn. N c to ra bi cc hot ng thng thng trong cuc sng

hng ngy

CTR dng khi ln (bulky waste) thng c kch thc ln, nhng c to ra

vi s lng tng i nh v vng i sn phm kh di.

CTR dng khi ln thng c to ra bi cc trng hp t khi xy ra nh vic

loi b mt gh bnh hay mt t lnh, lp li mi nh, ph hy mt tanh, hoc lm li

mt ng. Thnh phn ca CTR dng khi ln thng bin i nhiu hn thnh phn

CTR th.


8/36


Tm li, cc ngun chnh to ra CT th v CT dng khi ln: t nh dn, khu

bun bn thng mi, cc cng s, nhng phn ln CT dng khi ln li c to ra t

cc cng trng XD hay t vic ph d nh.

1.2 Khi lng cht thi rn

Khi lng c cho l thng s quan trng nht trong qun l cht thi rn. Khi

lng xc nh quy m v s lng thit b yu cu qun l cht thi rn. Khi lng

cht thi rn c th c biu th bng n v th tch (m3) hoc bng n v trng lng

(tn).u im ca vic o khi lng theo trng lng ch khng phi theo th tch l

ch trng lng thng khng thay i i vi mt tp hp cho trc ca cc vt b loi

b, trong khi th tch li bin i rt nhiu.

Khi lng cht thi rn thng c biu th bng kg trn u ngi trn ngy

cc dng cht thi cc vng khc nhau c th c so snh.

Khi lng ny c biu th bng cng thc sau:

Pcd = 1000T/365P (1.1)

Trong : Pcd: kilogam trn ngi trn ngy

T: khi lng tn CT c to ra trong mt nm, gm c CTR sinh

hot khu dn c v CTR sinh hot khu thng mi, c quan

P: dn s trong vng to ra cht thi

S lng thng k t cc tnh, thnh ph, nm 2004 cho thy lng cht thi rn

bnh qun khong 0,9n 1,2kg/ ngi.ngy cc th ln v mt s th nh dao

ng t 0,5 n 0,65kg/ngi.ngy. n nm 2008, con s ny tng ln

1,45kg/ngi/ngy cc th.

Khi lng cht thi th chim gn 50% trn tng s cht thi rn tan quc.

Kt qu nghin cu v lng pht sinh cht thi rn cc th cho thy, tng lng rc

thi sinh hot pht sinh t th c xu hng tng u, trung bnh t 10-16% mi nm.


9/36


Hnh 1.2 Thnh phn cht thi rn ton quc nm 2008 v xu hng thay i thi

gian ti (Ngun: Trung tm nghin cu v quy hoch mi trng th - nng thn, B

Xy Dng 2010)

Thnh phn cht thi th rt a dng t cht thi hu c (rc sinh hot t h

dn, ch, khu thng mi), cc cht do, thy tinh(chai, l) n cht thi rn xy dng

(xem bng 1.1)

T l phn trm cc cht c trong rc thi khng n nh, rt bin ng theo mi

a im thu gom rc, ph thuc vo mc sng v phong cch tiu dung ca nhn dn mi th. Tnh trung bnh, t l thnh phn cc cht hu c chim 45%-60% tng lng

cht thi; t l thnh phn nilng, cht do chim t 6-16% m trung bnh ca rc thi

t 46%-52%.

Bng 1.1 Thnh phn cht thi rn th (TPHCM)

Phn loi bc 1 Phn loi bc 2 V d

1.Giy Giy loi tr bo v tp ch Giy photocopy

Bo

Tp ch v cc loi c in n khc Cc t ri qung co

Giy ba c lp sn gn sng Ba c ph sp

Giy ba khng c lp sn gn sng Hp ng dy

Giy ba dung ng cht lnghoc c nhiu lp

T lt tr em


10/36


2. Cht do PET Chai nc khong

HDPE

LDPE

PVC

Khc Phim nh

a thnh phn Nha ABS

3. Hu c Xc gia sc, gia cm

Cht thi t qu trnh lm vn: l

cy, c v cc cht thi khc t qu

trnh ct ta

Thc phm

Phn gia sc, gia cm

Ph thi t cc nng sn

Vi v cc sn phm dt may

Sm, lp v cc sn phm cao su

Da

G Bao b g, pallet, mt ca

4. Kim loi en St

Bao b thic V lon

5. Kim loi mu Kim loi mu

Bao b nhm V lon

V chai bia, nc gii kht

Chai thy tinh trong

Chai thy tinh mu

Knh

7. Xy dng Gch ngi

B tng


11/36


t

Cc sn phm khc trong xy dng

8. Khc, nguy hitim tng

Cc cht thi nguy hi dng tronggia nh

Sn, cc bao b cha ha chtgia dng

Tro

Cht thi y t

Cht thi cng nghip

Khc

Ngun Qun l cht thi rn-cht thi nguy hi Ths V nh Long-Nm 2008

1.3 Tc ng n mi trng

CTR dng khi ln cng c kh nng lm suy gim cht lng mi trng v mt

m quan, lm mt khng gian c gi tr v lm nhim mi trng. N c th gy ra mi

nguy him chyn.CTR th cn l mt ngun vt liu th sn xut trong nh my,

lm nhin liu, lm vt liu ph trong nng nghip. Thch thc c bn trong qun l

CTR l phi gim thiu ti a cc tc ng c hi tim tng trong khi lm ti a ha

s phc hi CTR nh l mt ngun nguyn vt liu c gi v hu ch.

CTR c th lm suy thoi cht lng mi trng v mt thm m theo hai cch

sau y:

Th nht, nguyn liu cht thi m khng c cch ly mt cch hp l vimi trng (v d rc ri ba bi trn ph v mnh vn, mnh v trn mt

vng t trng) nhn chung l kh coi.

Th hai l cc phng tin, thit b qun l CTR th thng khng a nhn,v d nh cc bi rc thi trong vng ng bng, ni c mt dn c

cao v cc thit b t rc li t vng phi cng nghip.

Bi rc thng chim mt khong khng gian ln, vic gim lng pht thi cht

rn, ti ch, ti s dng, lm phn vi sinh v t rc, tt c u gp phn lm gim lng

t yu cu cho mt bi rc.t m c s dng chnlp rc thng kh c s

dng cho cc mc ch khc.Cc bi rc tip nhn cht thi rn th khng c x l

thng thm nc v s lng ng theo thi gian. Cc bi rc nh th s to ra kh metan


12/36


l mt cht kh gy chy n v cc cht kh khc trong vng 20 nm hoc lu hn na khi

cc bi rc ny ngng tip nhn rc.D cht thi trong mt bi rc c x l hay khng

c x l, nhn chung bi rc khng c th c canh tc li. R cy s ph hy lp t

khng thm c ph ln bi rc ng ca nhm lm gim lng nc r rc.

Ngun rc thi t cc h gia nh thng l cc loi thc phm chim t l cao

trong ton b khi lng rc thi ra. Kh hu nhit i nng m v ma nhiu nc ta

l iu kin thun li cho cc thnh phn hu c phn hy, thc y nhanh qu trnh ln

men, thi ra v to nn mi kh chu cho con ngi. Cc cht kh pht ra t qu trnh

ny thng l H2S, NH3, CH4, SO2, CO2. Thng thng th cc vn v mi nng nht

xy ra khi cht thi b thi ra nhanh, tiu th xy sn c v gy ra trng thi ym kh.

CTR dng khi ln thng khng gy ra cc vn v mi v n cha cc vt cht nhc th phn hy nhanh. Nhng CTR th thng gy ra cc mi b phn i, thm ch

khi c bao ph bng mt lp t ti trong mt bi rc.

Cc thit b t rc thng ngn nga c mi. phn vi sinh (compost) thng

gi c cht hu c nhng vn khng gy ra mi. Tuy nhin, qu trnh phn compost

yu cu k thut cn thn gim ti a vic to mi trong khi .

Bn cnh vic to mi, CTR c th cn gy ra cc dng nhim khc: Nc r rc

cha cc cht c lm nhim nc ngm v nc mt. Cc sn phm c hi, c tnh

n mn c sinh ra trong qu trnh t phi c ngn nga khng cho pht thi vo

bu kh quyn.

Mt chng trnh qun l CTR cng nn tm kim cc ngun li thu c t CTR

bao gm: ti ch, phn compost, t trc tip i i vi thu hi nng lng, ch bin

cht thi to ra nng lng v thu hi kh gas t bi rc lm nhin liu.

1.4. Cc ctnh ca cht thi rn

1.4.1 Tnh cht vt l ca cht thi rn

Nhng tnh cht vt l quan trng nht ca cht thi rn l khi lng ring,

m,kch thc, s cp phi ht, kh nng gi m thc t v xp ca cht thi rn.

1.4.1.1 Khi lng ring

Khi lng ring ca cht thi rn c nhngha l trng lng ca mt n v

vtcht tnh trn 1 n v th tch cht thi (kg/m3). Bi v khi lng ring ca cht thi

rn thay i tu thuc vo nhng trng thi ca chng nh: xp, cha trong cc t hng

cha container, khng nn, nn nn khi bo co d liu v khi lng hay th tch cht


13/36


thi rn, gi tr khi lng ring phi ch thch trng thi (khi lng ring) ca cc mu

rc mt cch r rng v d liu khi lng ring rt cn thit c s dng c lng

tng khi lng v th tch rc cn phi qun l.

Khi lng ring thay i ph thuc vo nhiu yu t nh: v tr a l, ma trong

nm,thi gian lu gi cht thi. Do cn phi thn trng khi la chn gi tr thit k.Khi lng ring ca cht thi th dao ng trong khong 180 400 kg/m3, in hnh

khong 300 kg/m3.

Phng php xc nh khi lng ring ca cht thi rn

Mu cht thi rn c s dng xc nh khi lng ring c th tch khong

500 lt sau khi xo trn u bng k thut mt phn t. Cc bc tin hnh nh sau:

1. nh mu cht thi rn vo thng th nghim c th tch bit (tt nht l

thng c th tch 100 lt) cho n khi cht thi y n ming thng.

2. Nng thng ln cch mt sn khong 30 cm v th ri t do xung 4 ln.

3. nh mu cht thi rn vo thng th nghim b vo cht thi nn

xung.

4. Cn v ghi khi lng ca c v thng th nghim v cht thi rn.

5. Tr khi lng cn c trn cho khi lng ca v thng th nghim thu

c khi lng ca cht thi rn th nghim.6. Chia khi lng cht thi rncho th tch ca thng th nghim thu c khi

lng ring ca cht thi rn.

7. Lp li th nghim t nht 2 ln v ly gi tr khi lng ring trung bnh.

1.4.1.2. m

m ca cht thi rn c biu din bng mt trong 2 phng php sau:

Phng php khi lng t v phng php khi lng kh.

Theo phng php khi lng t: m tnh theo khi lng t ca vtliu l phn trm khi lng t ca vt liu.

Theo phng php khi lng kh: m tnh theo khi lng kh ca vtliu l phn trm khi lng kh vt liu.

Phng php khi lng t c s dng ph bin trong lnh vc qun l cht

thi rn.

m theo phng php khi lng t c tnh nh sau:

a= {(wd )/ w} x 100 (1.2)

Trong : a: m, % khi lng


14/36


W: khi lng mu ban u, kg

d: khi lng mu sau khi sy kh 1050C, kg

Bng 1.2. m ca cc thnh phn trong cht thi rn th

Thnh phn % khi lng m (% khi lng)

Cht hu c

Thc phm tha

Giy

Giy carton

Nha

Vi vn

Cao su

Da

Cht thi trong vn

G

Cht v c

Thy tinh

Can thic

Nhm

Kim loi khc

Bi, tro,

9,0

34,0

6,0

7,0

2,0

0,5

0,5

18,5

2,0

8,0

6,0

0,5

3,0

3,0

70

6

5

2

10

2

10

60

20

2

3

2

3

8

Ngun: ISWM, McGraw-Hill 1993

1.4.1.3 Kch thc v cp phi ht

Kch thc v cp phi ht ca cc thnh phn trong cht thi rn ng vai tr rt

quan trng trong vic tnh ton v thit k cc phng tin c kh nh: thu hi vt liu,

c bit l s dng cc sng lc phn loi bng my hoc phn chia loi bng phng

php t tnh. Kch thc ca tng thnh phn cht thi c th xc nh bng mt hoc

nhiu phng php nh sau:

SC = l (2-2) (1.3)

SC = (l + w)/2 (1.4)

SC = (l + w + h)/3 (1.5)

SC = (l x w)1/2 (1.6)

SC = (l x w x h)1/3 (1.7)

Trong : SC : kch thc ca cc thnh phn


15/36


l : chiu di, (mm)

w : chiu rng, (mm)

h : chiu cao, (mm)

Khi s dng cc phng php khc nhau th kt qu s c s sai lch. Do tu

thuc vo hnh dng kch thc ca cht thi m chng ta chn phng php o lngcho ph hp.

V d: Tnh ton kch thc cp phi ht ca can nhm, can thic, thu tinh da

vo phng trnh 1.6

1.4.1.4. Kh nng gi nc thc t

Kh nng gi nc thc t ca cht thi rn l ton b lng nc m n c th

gi litrong mu cht thi di tc dng ca trng lc. Kh nng gi nc ca cht thi

rn l mt ch tiu quan trng trong vic tnh ton xc nh lng nc r r t bi rc.

Nc i vo mu cht thi rn vt qu kh nng gi nc s thot ra to thnh nc r

r. Kh nng gi nc thc t thay i ph thuc vo p lc nn v trng thi phn hu

ca cht thi. Kh nng gi nc ca hn hp cht thi rn (khng nn) t cc khu dn

c v thng mi dao ng trong khong 50-60%.

1.4.1.5. thm (tnh thm) ca cht thi c nn

Tnh dn nc ca cht thi c nn l mt tnh cht vt l quan trng, n schi phiv iu khin s di chuyn ca cc cht lng (nc r r, nc ngm, nc

thm) v cc kh bn trong bi rc. H s thm c tnh nh sau:

kCdK

2 (1.8)

Trong : K: h s thm, m2/s

C: hng s khng th nguyn

d: kch thc trung bnh ca cc l rng trong rc, m

: trng lng ring ca nc, kg.m2/s

: nht vn ng ca nc, Pa

k : thm ring, m2

S hng Cd2c bit nh thm ring. thm ring k = Cd2ph thuc ch

yu votnh cht ca cht thi rn bao gm: s phn b kch thc cc l rng, b mt

ring, tnh gc cnh, rng. Gi tr in hnh cho thm ring i vi cht thi rn

c nn trong bi rc nm trong khong 10-11 10-12 m2/s theo phng ng v

khong 10v 10 theo phng ngang.


16/36


1.4.2 Tnh cht ha hc ca cht thi rn

Thnh phn ho hc ca cc vt cht cu to nn CTR ng vai tr rt quan trng

trong vic nh gi cc phngphp; la chn phng thc x l v ti sinh cht thi. V

d: kh nng t chy vt liu rc ty thuc vo thnh phn ho hc ca CTR.

Nu CTR c s dng lm nhin liu cho qu trnh t th 4 tiu ch phn tchho hc quan trng nht l:

Phn tch gn ng s b im nng chy ca tro Phn tch cui cng (cc nguyn t chnh) Nhit tr ca cht thi rn.

Phn tch s bi vi cc thnh phn c th chy c trong cht thi rn bao

gm cc th nghim sau:

m (lng nc mt i sau khi sy 105oC trong 1 gi) Cht d chy bay hi ( khi lng mt i thm vo khi em mu cht thi

rn sy 1050C trong 1 gi t chy nhit 9500C trong l nung

kn)

C c nh (phn vt liu cn li d chy sau khi loi b cc cht bay hi) Tro (khi lng cn li sau khi t chy l h)

im nng chy ca tro

im nng chy ca tro c nh ngha l nhit t chy cht thi tro s

hnh thnh mt khi cht rn (gi l clinker) do s nu chy v kt t. Nhit nng

chy hnh thnh clinker t cht thi rn trong khong 2000 - 22000F (1100 - 12000C).

Phn tch cui cng cc thnh phn to thnh cht thi rn

Phn tch cui cng cc thnh phn cht thi ch yu xc nh phn trm (%) ca

cc nguyn t C,H,O,N,S, v tro. Trong sut qu trnh t CTR s pht sinh cc hp cht

Clor ho nn phn tch cui cng thng bao gm phn tch xc nh cc halogen.

Kt qu phn tch cui cng c s dng m t cc thnh phn ho hc ca

cht hu c trong cht thi rn. Kt qu phn tch cn ng vai tr rt quan trng trong

vic xc nh t s C/N ca cht thi c thch hp cho qu trnh chuyn ho sinh hc hay

khng.

Nhit tr ca cc thnh phn cht thi rn

Nhit tr ca cc thnh phn hu c trong thnh phn CTR th c th c xc

nh bng mt trong cc cch sau:


17/36


S dng ni hay l chng ct qui m ln S dng bnh o nhit tr trong phng th nghim Bng cch tnh ton nu TP ca cc nguyn t ho hc c x.nh

Do kh khn trong vic trang b l chng ct qui m ln, nn huht cc s liu

v nhit tr ca cc thnh phn hu c trong CTR th u da trn kt qu th nghim

s dng bnh o nhit tr trong phng th nghim.

Gi tr nhit to thnh khi t cht thi rn. Gi tr ny c xc nh theo cng

thc Dulng:

1.4.3 Tnh cht sinh hc ca cht thi rnCc thnh phn hu c (khng k cc thnh phn nh plastic, cao su, da) ca hu

ht CTR c phn loi v phng din sinh hc nh sau:

- Cc phn t c th ho tan trong nc nh: ng,tinh bt, amino acid v nhiu

acid hu c

- Bn cellulose: cc sn phm ngng t ca 2 ng 5 v 6 carbon

- Cellulose: sn phm ngng t ca ng glucose 6 carbon

- Du, m, v sp: l nhng ester ca alcohols v acid bo mch di

- Lignin: mt polymer cha cc vng thm vi nhm methoxyl (-OCH3)

- Lignocelluloza: hp cht do lignin v celluloza kt hp vi nhau

- Protein: cht to thnh t s kt hp chui cc amino acid

Tnh cht quan trng nht trong thnh phn hu c ca phn CTR th l hu ht

cc thnh phn hu c c th c chuyn ho sinh hc thnh kh, cc cht v c v cc

cht tr khc.S to mi hi v pht sinh rui cng lin quan n tnh d phn hy ca cc vt

liu hu c trong CTR th chng hn nh rc thc phm.


18/36


a. Kh nng phn hy sinh hc ca cc thnh phn hu c trong CTR: V cc

vi sinh vt c th chuyn ha giy, cht thi sn vn, cht thi thc phm v g, cht

thi ny c gi l c kh nng phn hy sinh hc.

Cc bng v sinh ch yu c th phn hy sinh hc c, tng t nh vy i

vi bng v dt may. Mt s vt liu cht thi c th phn hy sinh hc c s sn sngc chuyn ha hn so vi cc loi khc. Vt liu sn sng c chuyn ha nht l

nhng vt liu c nit cao, hm lng m cao: cht thi thc phm, v cc cht thi

xanh, nhuyn sn vn. Nhng cht thi ny c th b thi ra v tnh sn c v sinh

hc cao. Cht thi l cy nhn chung c tnh sn c v sinh hc mc trung bnh. G,

bng, len mc d c th c phn hy sinh hc u c tnh sn c v sinh hc kh thp

v c xem l khng phn hy trong khun kh qun l CTR.

Hm lng cht rn bay hi (VS), xc nh bng cch t chy CTR nhit

5500C, thng c s dng nh gi kh nng phn hy sinh hc ca phn hu c

trong CTR. Tuy nhin s dng gi tr VS m t kh nng PHSH ca phn hu c

trong CTR th khng ng bi v mt vi thnh phn hu c ca CTR rt d bay hi

nhng li km kh nng PHSH nh l giy in.

Thay vo hm lng lignin ca CTR c th c s dng c lng t l

phn d PHSH ca CTR, v c tnh ton bng cng thc sau:BF = 0,830,028LC (1.10)

Trong : BF : t l PHSH biu din trn c s VS

0,83 v 0,028 l hng s thc nghim

LC: hm lng lignin ca VS biu din bng % khi lng kh

Cc CTR vi hm lng lignin cao nh: giy in c kh nng PHSH km hn ng

k so vi cc cht thi hu c khc trong CTR th. Trong thc t cc thnh phn hu

c trong CTR thng c phn loi theo thnh phn phn hy chm v phn hu nhanh.

b. S pht sinh mi hi

Mi hi c th pht sinh khi CTR c lu gi trong khong thi gian di mt

ni gia v tr thu gom, trm trung chuyn, v ni chn lp. S pht sinh mi ti ni lu

tr c ngha rt ln, khi ti ni c kh hu nng m.

Ni mt cch c bn l s hnh thnh ca mi hi l kt qu ca qu trnh phn

hu ym kh vi s phn hu cc thnh phn hp cht hu c tm thy trong rc th.


19/36


V d, trong iu kin ym kh (kh), sunphat SO42- c th phn hu thnh sunfur

S2-

, v kt qu l S2-s kt hp vi H2to thnh hp cht c mi trng thi l H 2S. S

hnh thnh H2S l do kt qu ca 2 chui phn ng ho hc

Nc rc ti bi rc c mu en l do kt qu hnh thnh cc mui sulfide trong

iu kin ym kh. Nu khng c s hnh thnh cc mui sulfide th vic hnh thnh mi

hi ti BCL l mt vn nhim mi trng c tnh cht nghim trng

c. S pht trin ca ruiTrong ma h hay l trong khu vc kh hu nng m, s nhn ging v sinh sn

ca rui l vn quantrng cn quan tm ti ni lu tr CTR. Rui c th pht trin

trong thi gian 2 tun sau khi trng c sinh ra. i sng ca rui nhng t khi cn

trong trng cho n khi trng thnh c th c m t nh sau:

Trng pht trin 8-12 gi

Giai on I ca u trng (gii) 20 gi

Giai on II ca u trng 24 gi

Giai on III ca u trng 3 ngy


20/36


Giai on nhng 4-5 ngy

Tng cng 9-11 ngy

Giai on pht trin ca u trng trong cc thng cha rc ng vai tr rt quan

trng v chim khong 5 ngy trong s pht trin ca rui. hn ch s pht trin ca

rui th cc thng lu tr rc nn b thng rng trong thi gian ny hn ch sdi chuyn ca cc loi u trng.

1.4.4 S bin i tnh cht l hc, ha hc v sinh hc ca cht thi rn

Cc tnh cht ca cht thi rn c th c bin i bng cc phng php l, ha,

sinh hc. Khi thc hin qu trnh bin i th mc ch quan trng nht l mang li hiu

qu bi v s bin i cc c tnh ca cht thi rn c nh hng rt ln n k hoch

pht trin v qun l cht thi rn.

a. Bin i vt l

Phn loi cht thi rn: Qu trnh ny nhm tch ring thnh phn cht thi rn

nhm chuyn cht thi t dng hn hp thnh dng tng i ng nht thu hi cc

thnh phn c th ti sinh, ti ch. Ngoi ra c th tch nhng thnh phn cht thi nguy

hi v nhng thnh phn c kh nng ti thu hi nng lng.

Gim th tch bng c hc: Phng php nn, p thng c s dng gim

th tch cht thi, thng s dng nhng xe thu gom c lp ghp b phn p nhm lmtng khi lng rc thu gom trong mt chuyn. Nhng loi nh giy, carton, nha, lon

nhm, lon thic khi thu gom thng c ng kin gim th tch cha, chi ph x l

v vn chuyn. ng thi phng php ny cn lm tng thi hn ca cc bi chn lp

cht thi. Gim kch thc bng c hc nhm lm gim cht thi c kch thc ng nht

v nh hn kch thc ban u.

b. Bin i ha hc

Bin i ha hc nhm lm thay i thnh phn cc pha (v d t rn sang lng,

hoc rn sang kh). Mc ch l lm gim th tch v thu hi cc sn phm bini bao

gm cc phng php sau:

t: t l phn ng ha hc gia oxy v cc thnh phn hu c trong cht thi

sinh ra cc hp cht thi b oxy ha cng vi s pht sng v ta nhit.

Lng khng kh cp d m bo qu trnh t xy ra hon ton, sn phm cui

ca qu trnh t chy bao gm khng kh nng cha CO2. H2O, khng kh d v phn

khng chy cn li. Trong thc t ngoi nhng thnh phn ny cn c mt lng nh cc

kh NH3,SO2,NOx, v cc kh vi lng ty thuc vo bn cht ca cht thi.


21/36


Nhit phn: Hu ht cc cht hu c u khng bn vi qu trnh nung nng,

chng c th b phn hy qua cc phn ng bi nhit v ngng t trong iu kin

khng c oxy to thnh nhng sn phm dng rn, lng, kh.

Kh ha: Qu trnh ny bao gm qu trnh t chy mt phn nhin liu Cacbon

thu nguyn liu chy v kh CO, H2v mt s nguyn t hydrocacbon trong CH4

c. Chuyn ha sinh hc

Bin i sinh hc cc thnh phn hu c trong cht thi vi mc ch l lm gim

th tch v trng lng ca cht thi, sn xut phn compost, cc cht mn lm cho n

nh t, kh mtan. Cc loi vi khun, nm, men ng vai tr rt quan trng trong vic

bin i cc cht hu c. Qu trnh bin i ny xy ra trong iu kin ym kh v hiu

kh ty thuc vo s hin din ca oxy tn ti hai phng php l phn hy hiu kh v

phn hy k kh.

Qu trnh phn hy k kh: L qu trnh chuyn ha cc cht hu c trong cht

thi rn th trong iu kin k kh xy ra theo 3 bc:

Qu trnh phn hy cc hp cht c phn t lng ln thnh nhng hp cht thch

hp l ngun nng lng.

Qu trnh chuyn ha cc hp cht sinh ra t bc 1 thnh cc hp cht c nng

lng thp hn.Chuyn i cc hp cht trung gian thnh cc sn phm ring l, ch yu l CH 4

v CO2

u im

Chi phu t thp Thu hi c kh phc v cho sn xut. Trong qu trnh s tn ti mt s loi vi sinh, vi khun gy bnh v nhit

thp. Khi cht thi vi khi lng 1000 tn/ngy mi c hiu qu v kinh

t.

Nhc im

Thi gian phn hy xy ra kh lu t 4-12 thng. Kh sinh ra c mi hi v kh chu gy nh hng ti sc khe cng ng.

Qu trnh phn hy hiu kh: Qu trnh ny da vo s hot ng ca vi khun

hiu kh khi c mt ca oxy, khong hai ngy nhit tng vo khong 450C sau 6-7

ngy nhit t t 70 75% y l nhit thch hp cho vi sinh vt phn hy cht

hu c.


22/36


u im:

Chi ph u t thp, sn phm phn hy thp. Cht thi phn hy nhanh sau 2-4 tun. Vi sinh vt gy bnh b cht nhanh do nhit tng.

Nhc im

Chi ph x l cao K thut phc tp Trong qu trnh vn hnh cn duy tr mt s c trng trong qu trnh .

Bng 1.3 Qu trnh bin i vt l, ha hc v sinh hc ca cht thi rn

Qu trnh bin i Ph.php bin iBin i hoc thay i c bn

sn phm

L hc

- Tch loi theothnh phn

- Gim th tch- Gim kch thc

- Tch loi bng tayhoc my

- S dng lc hoc psut

- S dng lc ct,nghin hoc xay nh

- Cc thnh phn trong hn hp

cht thi th

- Gim th tch ban u

- Bin i hnh dng ban u

Ha hc

- t- S nhit phn

- Kh ha

- xy ha bng nhit- S chng ct, phnhy

- t thiu kh

- CO2, SO2, sn phm xyha khc, tro

- Kh gm hn hp kh, cndu v than

Sinh hc

- Hiu khcompost

- K kh phnhy

- K kh compost

- Bin i SH hiu kh

- Bin i SH k kh

- Bin i SH k kh

- Phn compost- CH4, CO, sn phm phnhy cn li: mn hoc bn

- CH4, CO2, rc cn liNgun Qun l cht thi rn Nguyn Vn Phc

1.5 c tnh khi lng cht thi rn

Phng php tt nht c tnh khi lng cht thi l lp t c nh cc cn

ni tiu hy cht thi v cn tng xe ti trn ng vo v c lc ra na. Nhiu ni tiu

hy CTR c lp t cc cn, nhng ti mt s bi rc th vn cn cha lp.


23/36


Do vic c tnh th tnh CTR trong mt xe ti ch rc hay con-ten-n ch rc

ng kn hoc ph kn l khng d dng nn th tch cn o c ghi li chnh l cng

sut ch ca cc xe ti hoc con ten n. Bi v cch c tnh ny s to nn s khuyn

khch chuyn ch rc trn cc xe ti cht y, nn s liu th tch rc c ghi li s gn

vi th tch rc thc t.

Vic biu th khi lng cht thi bng n v tn c a chung hn l bng

yard khi. Sau y l biu thc chuyn i:

M = VD/2000 (1.11)

Trong : M : khi lng cht thi rn c o bng tn

V : th tch cht thi c o bng yard khi

D : T trng cht thi c o bng pounds trn yard khi

nhng ni tiu hy rc m khng lp t cn c nh, c th s dng cn xch

tay c tnh tn cht thi ang c vn chuyn. Cc xe vn ti s c la chn v

cn, cc kt qu s c dng c tnh trng lng ton b ca dng cht thi.

S lng rc tng cng s c c tnh theo phng trnh sau :

W = T(w/t) (1.12)

Trong :

W l trng lng tng cng ca cht thi c vn chuyn n thit b/ni tiuhy rc

T : Tng s lng cc xe vn ti chuyn ch cht thi n thit b/ni tiu hy rc

w : trng lng tng cng ca cc xe vn ti c cn

t : s lngxe vn ti c cn

Cch tip cn ny thng ph hp vi nhng ni tip nhn mt lng xe vn ti

tng i n nh. Tht ng tic l t l m cc xe vn ti vn chuyn rc n ni/thit

b tiu hy lun dao ng trong ngy.

Mt cch tip cn tt hn l cn c cng nhiu xe vn ti n trong ngy cng

tt, ri theo di tng s lng xe vn ti m chuyn ch cht thi rn trong tng

gi.Trng lng trung bnh ca mt xe vn ti ring r v tng trng lng phi c

tnh ton cho tng gi, v ri tng ca tng gi c cng li thnh tng cho mt ngy.

Phng trnh 1.12 c iu chnh nh sau :

W = T1(w1/t1) + T2(w2/t2) + ..... + Tn(wn/tn ) (1.13)

W = Tng trng lng cht thi c chuyn ch ti ni/thit b tiu hy


24/36


T1= s lng xe vn ti chuyn ch cht thi ti ni/thit b tiu hy trong gi

u tin

T2= s lng xe vn ti chuyn ch cht thi ti ni/thit b tiu hy trong gi

th hai.

Tn= s lng xe vn ti chuyn ch cht thi ti ni/thit b tiu hy trong gicui cng ca ngy vn hnh

w1= trng lng tng cng ca cc xe vn ti trong gi u tin

w2= trng lng tng cng ca cc xe vn ti trong gi th hai

wn= trng lng tng cng ca cc xe vn ti trong gi cui cng ca ngy vn

hnh

t1= s lng xe ti c cn trong gi u tin

t2= s lng xe ti c cn trong gi th hai

tn= s lng xe ti c cn trong gi cui cng ca ngy vn hnh

Vic c tnh chnh xc ca cc kt qu v mt thng k thng phc tp khi

m t s cc xe vn ti c cn so vi cc xe cha c cn s thay i t gi ny sang

gi khc.

1.5.1 Ly mu cht thi rn th c tnh thnh phn

V trong tt c cc s dng thng k da trn vic ly mu, th s thu mu l mtbc quan trng, mang tnh then cht c tnh thnh phn cht thi rn th. Cc

xem xt v mt nguyn tc trong vic thu mu c th hin nh sau:

Mi kg cht thi trong dng cht thi phi cmt c hi nh nhau c thhin trong cc kt qu cui cng.

S lng cc mu cng ln th chnh xc ca kt qu cng cao S thay i gia cc mu cng ln th cng nhiu mu phi c phn loi

nhm t c mt mc chnh xc cho trc.

Thi gian dnh cho vic thu mu cng ln th thi gian dnh cho vic phnloi mu li cng t i.

Cng nhiu cht thi c x l trc khi phn loi th cng kh khn v tchnh xc phn loi.

Vn c bn l thi on thu gom mu. Nhn chung, giai on mt tun c

s dng bi v hu ht cc hot ng ca con ngi v hu nh cc k hoch thu gomph thi u da trnc s mt tun. Vic ly mu trong vng mt tun i vi mi ma

trong mt nm thng c a dng hn. Ly mu vo ma xun th c bit quan trng


25/36


bi v cht thi sn vn c sinh ra trong thi gian ny l ln nht v vo ma ng l

nh nht, v loi cht thi cng thay i nhiu nht.

Vn c bn khc na l hoc thu gom mu cc v tr ni cht thi c to ra

hay thu gom cht thi ni/thit b tip nhn cht thi. Vic ly mu ni/thit b tip

nhn cht thi c a dng hn. Tuy nhin, thu gom mu nhng v tr to ra cht thic th cn thit trong nhng trng hp sau y:

Mc tiu u tin l m t cht thi c to ra bi mt ngun no , nhl cc loi bun bn c th.

Xc nh cc ni m cht thi c tip nhn m nhng ni ny khng cth c d bo vi tin cy cho bt k mt tun cho trc no.

Cc ni tip nhn cht thi m phn b rng khp lm cho vic ly mukh khn hn v chi ph nhiu hn cho c vic ly mu v hot ng phn

loi

Kh c th tip cn ti ni/ti thit b tip nhn cht thi. Ti ni/thit b tip nhn CTR, khng c ch dnh cho hot ng phn

loi rc

Vic ly mu cc v tr to ra CTR c th s t hn v t c gi tr hn so vi

vic ly mu ti ni/thit b tip nhn CTR. Chi ph ph thm l do cc n lc c yucu tng thm thit k cng ly mu v thi gian di chuyn lin quan n vic thu

gom cc mu.C 2 nguyn nhn c bn lm gim tnh hp l ca vic ly mu ti ni

CTR c to ra:

Th nht, cht thi c th kh thu cbi v n nm trn a phn cnhn m khng th ra vo mt cch t do c, hoc cht thi rn li

trong cc thit b nn p rc. Mt s cht thi li khng tip cn c vo

ban ngy bi v chng khng c trong cc thng cha rc ngoi tri

cho ti khi kt thc gi lm vic v chng s c ly i vo sng sm

hm sau.

Th hai, mt phn tng i cht thi c i din bi tng thng charc th li cha bit bi v tn sut thu gom v khi lng rc trung bnh

trong thng cha rc ti mi ln thu gom (pick up) th cng khng bit.

Vic la chn mt cch ngu nhin cc thng cha rc ly mu dnn vic ly mu khng ng cch nhiu thng cha ang hot ng,

cha nhiu cht thi.


26/36


CTR th khu dn c thng tip cn d dng ly mu t cc l ng vo

ngy thu gom. Bi v cc h dn c to ra mt khi lng rc thi tng t nhau, vic la

chn mt cch ngu nhin cc h gia nh ly mu s cho mi kg cht thi mt tn

sut tng t trong mt mu. Hn na, bi v c tnh ca CTR th nht qun t h gia

nh ny sang h gia nh khc hn l t cng s ny sang cng s khc, nn nhng thiust trong mt chng trnh ly mu CTR sinh hot nhn chung t quan trng hn nhng

thiu st trong mt chng trnh ly mu CTR thng mi (commercial). Mt chng

trnh chung ly mu CTR t cc a im to ra cht thi l khng th thc hin ci

vi Nh nc bi v cc tnh hung thay i rt ln t ni ny n ni khc, t nghin

cu ny n nghin cu khc. Sau y l cc nguyn tc chung cn tun theo:

Thu thp cc mu t nhiu lnh vc khc nhau trong vng nghin cu cngnhiu cng tt m khng lm qu ti vic ly mu trong cc lnh vc quan

trng.

Nu c th, vic thu mu t cc v tr bun bn, thng mi nn t l thunvi ln ca cc ni cha CTR v t l vi tn sut chuyn ch cht thi

(pick-up).

Thu mu t cc khu dn c c cn h ring bit v t khu chung c nn tl vi s lng ngi sng trong

Yu cu nhng ngi i thc a khng c t do lm theo mnh trongvic la chn cc v tr thu mu

Vic thu mu ti ni/thit b tip nhn CTRthng r hnvic thu mu ti cc v

tr sinh ra CTR v thng c kh nng to ra cc kt qu c gi tr. L do l v khng yu

cu vic di chuyn, i li. Cc mu m thu thp c ti ni/thit b tip nhn CTR

thng i din cho CTRang c quan tm bi v chng c la chn mt cch in

hnh t mt dy cc xe ti n l c bit cc thng s v ln m cha ng ton

b dng cht thi.Vic thu mu ti ni/thit b tip nhn CTR gm hai giai on:

La chn xe ti ly mu Thu mu t lng cht thi c x ra t cc xe ti c la chn trong

bc trc .

1.5.2 La chn mu

Cc k s mi trng thng la chn cc xe vn ti n l ngoi thc a ly

mu, nhng h c th la chn trc cc xe ti m bo chc chn rng cc tuyn thu


27/36


mu c th u c mt trong cc mu. Cc phng php c th thc hin c la

chn cc xe ti ngoi thc a nh sau:

- Khong thi gian khng i- To ra s ngu nhin- Phn phi gia cc ngun cht thi

Khong cch ly mu khng i c th hin nh sau:

- Tng xe ti th nh nth- Tng tn cht thi th nth- Tng mt khi cht thi th nth- Mt xe ti c sau n pht

Thu gom mt mu t mi mt xe ti th n th tng i n gin nhng li lm

cho cht thi trong mi xe ti nh hoc mt phn cc xe ti ch y ri vo tnh trng b

qu i din (overrepresented) trong cc mu.

Thu gom mt mu t xe ti cha mi tn cht thi th n th l tng nhng trong

thc t li kh khn bi v trng lng ca mi xe ti theo quan trc l khng r rng.

Thu gom mt mu t xe ti cha mi m3cht thi th n th kh thi hn bi v th

tch ca hu ht cc xe ti c th c xc nh thng qua quan trc. Tuy nhin, vic ly

mu da vo th tch xe vn chuyn c xu hng lm cho cht thi khng c nn p.Khong cch gia cc ln ly mu c da vo mt tp hp s lng cc xe vn

chuyn hoc mt tp hp khi lng cht thi s gy ra s dao ng trong nhp vn

hnh ly mu trong tng ngy lm vic ngoi thc a. S dao ng ny c th dn ti

vics dng nhn lc khng hiu quv lm chch kng k hoch ban u vch ra.

Cch tip cn ny cng gy ra tnh i din qu mc ca cht thi khi n vo thi im

mun trong ngy v khongt gia cc xe ti vn chuyn c xu hng ko di ra vo phn

cui ca ngy v bi v cc xe ti n mun thng c xu th ch khng y, c bit

nu chng li c tnh bng tn ch khng phi tnh bng m3.

Vic t c cc mu theo yu cu phn loi th tng t nh vic thu mt

mu c sau n pht v chng u c nhng nhc im nh nhau.Khong cch ly mu

mt cch ngu nhin c cng nhc im nh l khong cch ly mu khng i tng

ng cng vi mt s nhc im ph thm sau y:

- Khong cch ly mu ngu nhin s lm tng kh nng i ly mu ngoithc a i khi phi n khng ngi ri, hoc i khi phi lm thm ngoi

gi


28/36


- Khong cch ly mu ngu nhin s lm tng kh nng b l cc xe ti c la chn khi m c qu nhiu xe ti n mt cch ngu nhin trong

mt khong thi ngn.

Trong nhiu trng hp, vic ly mu theo ngun cht thi s lm gim ti a cc

vn i km theo cc kiu ly mu theo khong cch ny. Cc ngun cht thi m t cc mu c th c la chn bao gm cht thi th, cht thi t cc xe gong n l,

t cc tuyn thu gom c bit, t cc khu vc to ra cht thi nh khu dn c v khu

thng mi v cc ngun c th nh t khch sn, hoc t cc chung c. Nhn chung,

vic ly mu theo ngun s c ngha nu nh vic cung cp thng tin mt cch y

v khi lng cht thi t mi ngun c ly mu. Cc mu c th c thu gom t

tng ngun t l thun vi khi lng cht thi t mi ngun, hoc cc kt qu thnh

phn i vi cc ngun khc nhau c th c ly theo trng s da trn khi lng t

mi ngun.Tt nht l, ni/thit b tip nhn CTR c sn cn v mt ngn hng d liu

my tnh cha ng nhng thng tin sau y v ti lng cht thi:

trng lng thc ca cht thi, loi cht thi, loi xe vn ti chuyn ch cht thi, v loi xe gong thu gom c thu gom t th no ban u.Thng tin ny s c kt hp vi cc thng tin trong hp ng chuyn ch cht

thi trong mi th c tnh mt cch hiu qu khi lng CTR th t khu dn c

v t khu thng mi, bun bn.Cc dch v cng ch (thuc quyn qun l ca chnh

quyn thnh ph) tronng cc th thng chuyn ch CTR t cc khu dn c, cn cc

dch v t nhn thng ph trch chuyn ch cht thi rn khu bun bn, thng mi.

Trong mt s trng hp khc, chnh quyn thnh ph thng k hp ng vi dch v

chuyn ch t nhn thu gom cht thi khu dn c. Cht thi dn c v cht thi

thng mi, bun bn cng c th c phn bit bi loi xe vn chuyn m c s

dng chuyn ch cht thi.Nu ni/thit b tip nhn CTR khng c sn cn, ngi ta

c th ghi chp li V cht thi trong vic thit k k hoch ly mu nhng phi phn bit

gia cht thi c nn p v cha c nn p. Nhiu ni/thit b tip nhn CTR

nhn rt t cht thi th cha c nn p, trong khi nhng ni khc li tip nhn mt

khi lng ng k loi cht thi cha c nn p ny. Bi v tnh theo bnh qun u

ngi th cht thi dn c c to ra tng i thng nht nn c th s dng s li u

dn s phn b cc mu cht thi dn c trong s cc th nu nh khng sn c cc


29/36


bn ghi khi lng cn thit. i ng nhn s ngoi thc a phi phng vn cc xe vn

chuyn t nhn n ni/thit b nhn rc bit v ngun gc cht thi ch n. Thng

tin c cung cp t nhng i vn chuyn ny thng khng c y . Trong mt

vi trng hp, thng tin ny c th c b sung hoc c chnh sa trong qu trnh

phn loi mu.

1.5.3 Thu mu

Hu ht cc chng trnh ly mu bao gm c ASTM D 5231 u khng nh rng

mi mt xe ti c la chn th nn c hng dn x cht thi trong vng c

quy nh thu mu. ASTM D 5231 cng khng nh rng b mt m cht thi s c

x xung nn c dn sch s nhng trong hu ht cc nghin cu, vic ngn nga mt

mu khng cho cha mt s lng vt cht t mt khi lng cht thi khc nhau l

khng cn thit.

Vic la chn mt phng php ly mu i hi s nh gi v bn cht ca CTR

th c x t mt xe ti c nn p theo tiu chun ln b mt ca mt bi rc hoc

ln mt mt phng c lt. Cht thi c xu hng gi c hnh dng ca n vn c

khi c ch trong xe ti ch khng phi s thnh mt ng xp mm.Ti cht thi

c c th cao t 7 n 8 fit.Trong nhiu ng rc, cc ti rc b nn li vi nhau

cht n mc m rt kh khn ko vt cht ra khi ng rc. Mt s cht thi thngb tt khi nh hoc b tt sang mt pha ca ng rc, nhng cht thi xp v lng lo

ny khng nn c s dng ly mu bi v n c th c nhng c im khng i

din.Nhn chung, mt mu nn c la chn mt cch ngu nhint mi xe vn ti

c la chn nh c ch ra trong ASTM D5231. Nu nhiu mu phi c ly t

mt ng rc th nn thu gom cc mu t nhiu phn khc nhau ca ng rc.

Vn u tin l kch c mu c thu gom t mi xe vn chuyn. Ngi ta

s dng cc kch c mu khc nhau, thay i t 50lb ti ton b ng rc.

Cc mu lnc cc u im sau y:

-S bin thin ( lch chun) gia ccmu th nh hn v vy mt s mu t hn

c yu cu t c mt mc chnh xc cho trc.

-S phn b kt qu phn loi cc mu th gn vi phn b chun hn (ng

cong hnh chung)

-Phm vi ranh gii gia mu v phn cn li ca ng rc th nh hn, tng xng

vi th tch ca mu


30/36


B

C

DA

Cc mu nhthng c u im l thi gian phn loi mu v thu gom mu ngn

hn. Ngi ta nht tr rng kch c mu ti u khong t 200 n 300 lb (90,8 kg

136,2 kg) t cc ng CTR th bao gm:

Tp hp mt mu t hp t vt cht c ly t cc im c xc nhtrc trong ng rc (v d nh l tng gc hay l ti im gia ca mipha)

To thnh hnh nn v chia u thnh bn phn Thu gom mt mu bng gu ngom t mt im c la chn ngu

nhin

Thu gom th cng mt ct cht thi t mt v tr c la chn ngu nhin.Nhc im c bn ca cc mu t hp th ging nh nhc im ca cc mu

nh: phm vi bin ly mu ln buc nhng ngi ly mu phi a ra qu nhiu quyt

nh liu c gp cc loi cht thi trong mu khng. Mt mu t hp c xu hng l mt

mu nh gi hn l mt mu ngu nhin. Nhc im th hai ca cc mu t hp l

chng mt nhiu thi gian hn thu gom nu so snh vi mu gu (grab) hoc mu ct

(column). S bin i ca ly mu t hp l phi thu gom tng mu t nhng ng cht

thi khc nhau.

Trong bc to thnh hnh nn v chia u thnh bn phn,nhng ngi ly mu trn mt khi lng ln cht thi lm cho cc

c tnh ca n ng u hn, ri sp xp cht thi c trn vo mt ng hnh nn

v la chn ngu nhin mt phn, thng l mt phn t ca ng cht thi c trn.

Mc ch: kt hp cc u im v mt thng k ca cc mu ln vi thi gian phn

loi cc mu nh hn c gim i. Qu trnh sp xp thnh hnh nn v chia u

ng cht thi thnh 4 phn c th c lm vi c ng cht thi hoc ch vi mt phn

cht thi v c th c thc hin mt ln hoc nhiu ln nhm t c mt mu n.

ASTM D 5231 ch r mt vng nn v chia t, bt u khong 1000 lb (454 kg) cht

thi rn nhm t c mt mu khong t 200 n 300 lb (90,8 kg 136,2 kg).

To thnh hnh nn v chia t (coning and quartering) tim n nhng kh khn

nu so snh vi ly mu gu (grab) hoc ly mu ct v c nhng nhc imnh sau:

V c bn l lm tng thi gian ly mu i hi c khng gian rng C xu hng lm rch, gy cc ti rc, lm cho vic x l cht thi kh khn hn

nhiu.


31/36


Lm tng thi gian phn loi rc do lm ph v cc cm rc cc loi. Yu cu s dng mt my cht ti kiu ko (front-end loader) trong mt giai on

kh di. Nhiu ni/thit b tip nhn CTR c th to ra mt my cht ti kiu ko

v lun phi c ngi vn hnh trong cc giai on ngn; nhng mt vi ni/thit

b tip nhn CTR khng c th cung cp mt my cht ti kiu ko trong cc giaion di hn c yu cu cho to hnh nn v chia t.

chnh xc ca vic phn loi rc b gim i do c s tng ln v phn trm chtthi thc phm b dnh vo hoc b hp ph vo cc thnh phn cht thi khc.

Lm tng tn tht m t mu Thc y s phn tng cht thi do t trng v c ht. gim thiu kh nng

phn tng ny th mu ly phn t phi mt mt phng vi cnh thng ng v

cc im nm trung tm hnh nn. Thc t th hnh dng ny rt kh c th t

c.

u imca to hnh nn v chia t l n lm gim i s khc nhau gia cc mu

( lch chun), gim s lng mu cn phn loi. To hnh nn v chia t c cho

l hp l nu nh n lm gim lch chun b p nhng nhc im v nhng

kh khn tim tng.

Nu to hnh nn v chia t c lm mt cch hon thin v y th vic phnloi mu cui cng s tng ng vi vic phn loi ton b nn cht thi, v lch

chun c gim mt cch ng k. V s lng cc mu phi c phn loi t

c mt mc chnh xc cho trc th t l vi bnh phng lch chun, vic to

nn v chia t c th lmgim mt cch ng k s lng mu c yu cu. Tuy nhin,

lu rng cng thc hin vic to nn v chia t k lng th tng nhc im cng nh

tng kh khn tim tng lun i km theo phng php ny li cng r rt.

Mt phng php ly mu CTR thng dng hn l thu mt mu gu c s

dng mt my cht ti kiu ko. Phng php ny tng i nhanh v thng c th

c lm bi nhn lc ph trch thit b m khng can thip qu mc vo vic vn hnh

thit b thng thng. Vic ly mu bng my cht ti kiu ko s lm gim tc ng

tim tng v s thin v ca ngi ly mu thng xy ra vi cc phngphp ly mu

th cng, nhng li tim n nhng loi thin v khc nh sau:

Ging nh ly mu bng xng, vic ly mu bng my cht ti kiu ko cxu hng thun li cho cc vt th nh v c chc hn l cc vt th nh

v to. Cc vt th nh v to c xuth b y i hoc b ri xung khi m ci


32/36


gu ca my cht ti kiu ko c lp t, c nng ln, hoc c rt

ra.

Mt khc, vic lm gy, t cc ti cha rc khi gu ca my cht ti kiuko xm nhp su vo ng cht thi th c xu hng gii phng cc vt

cht mn, c chc khi nhng ti ny, iu lm gim tnh i din cavt cht ny trong mu.

Cc mu ly bng my cht ti kiu ko trn b mt t th thin v chtthi ri xung t nh hoc t cc pha ca ng cht thi m chng c th

khng c cc c tnh nh l cc cht thi vn cn li trong ng. Trn

cc b mt bm bi, cc mu ly bng my cht ti kiu ko trn b mt t

c th b nhim bn bi bi.

Tc ng ca nhng nhn t khng khch quan ny c th c gim i nu nh

mu c ly cn thn v i ng ly mu phi chnh sa cc ngun gy ra s khng

khch quan, v d nh cc vt th nng ri xung t gu khi n c nng ln. Trong

phng php ly mu bng my cht ti kiu ko, nhn lc ly mu c th dng cc im

ly mu khc nhau cho cc ti khc nhau m bo chc chn rng cc lp cht thi

khc nhau theo phng ng v phng ngang u c i din trong mu. C th thay

i im ly mu hoc l ngu nhin hoc l theo kiu lp li. Phm vi thin lch m cth xut pht t vic s dng cc im ly mu ging nhau cho mi ng cht thi th

khng c bit.Mt nhc im c hu ca phng php ly mu bng my cht ti

kiu ko l kh khn trong vic c tnh trng lng cc mu. Trng lng ch c th

c c tnh da trn th tch, v cc mu c th tch bng nhau li c trng lng khc

nhau.

Mt phng php ly mu CTR t ph bin hn l thu gom th cng mt ct cht

thi rn hp t mt v tr c la chn ngu nhin trn b mt ng cht thi, ko di t

y n nh ng cht thi. Phng php ny c nhng u im nh sau:

khng yu cu bt c thit b nng no thi gian ly mu tng i ngn Do cc lp khc nhau trong ng cht thi theo phng ngang u c ly

mu, nn cc mu s i din nhiu hn so vi phng php ly mu bng

gu s dng mt my cht ti kiu ko. Tuy nhin, lu rng cc ng cht

thi cng b phn tng pha trc ra pha sau, v cc mu ly theo ct

khng i din cho cc lp khc nhau theo phng ng.


33/36


Nhc im chnh ca phng php ly mu theo ct l ch vic ly cht thi

bng th cng t pha b nn cht ca ng cht thi th rt kh khn v nguy c b cc

vt thng ct v chch t vic ko cc cht thi l ln.

Trong s nhiu quy trnh ly mu lai ghp m kt hp cc c im ca 4 quy

trnh chung ny, c hai quy trnh kh l thch hp vi s lu c th.Th nht, trong quy trnh ly mu c ch r ASTM D 5231, mt my cht

ti kiu ko c th loi b t nht l 454 kg(1000lb) vt cht dc theo ton b mt pha

ca ng cht thi; sau ng cht thi s c xo trn, to nn v chia t to ra

mt mu nng t 90,8 n 136 kg (t 200 n 300 lb). So snh vi phng php ly mu

bng gu c s dng mt my cht ti kiu ko, phng php ATSM c u im l to ra

cc mu mang tnh i din cho cht thi tt hn, nhng li c nhc im l lm tng

thi gian ly mu.

Trong mt quy trnh ly mu lai ghp th hai, mt my cht ti kiu ko lm ti

mt khi lng nh cht thi t mt im c la chn ngu nhin hoc t mt ct

trong ng cht thi, v mu c thu th cng t ng cht thi c lm ti ln.

Phng php ny th an ton hn phng php ly mu theo ct th cng v kim

sot c trng lng ca mu nhiu hn l ly mu bng my cht ti kiu ko. Phng

php ny ch yu trnh c cc thin lch tim n ca ly mu bng my cht ti kiuko nhng li c xu hng thin lch do ngi ly mu.

1.5.4 Phn loi v cn mu cht thi rn th

Trong hu ht cc trng hp, vic phn loi CTR nn c xem nh l mt hot

ng cng nghip ch khng phi l mt ng.cu trong phng th nghim. Trong khi

chnh xc l rt cn thit th vic o chnh xc ph hp li l ounces ch khng phi l

gam hay hay l mg. Nu c nht nh i hi c mt mc chnh xc cao qu th s lm

chm li qu trnh phn loi, gim s lng mu c th c phn lo i.

Ln lt, s gim ny s lm gim chnh xc thng k ca kt qu. Trong case

m mt hot ng yu cu mt mc chnh xc l 10% th khng chnh xc l 1%

khng c cho l quan trng lm.Cc nguyn l v hot ng cng nghip ng dng

cho phn loi CTR bao gm gim thiu ti a s di chuyn ca cng nhn, duy tr s

thoi mi v khch l cng nhn.

a.Ly mu cht thi rn th phn tch trong phng th nghim

t c cc kt qu th nghim c ngha i vi CTR th th kh khn.

Cc ngun kh khn c bn l:


34/36


s c mt ca nhiu loi vt th khc nhau trong CTR th v kch c ln ca cc vt th ny.

Thu gom cc mu nh nhng mang tnh i din t mt ng ng nht cc vt

th nh (v d nh ng go) th d dng hn t mt ng cc vt th ln khng ng

nht. Cc ngun kh khn th cp trong ly mu CTR th bao gm s phn b khngng u ca m v cc quy trnh th nghim khng trc sau nh mt. Thnh phn

ca CTR khng mang tnh cht ng nht. vic xc nh thnh phn ca cc cht thi

khng phi l cng vic n gin.

Cng vic kh khn nht trong vic thit k v vn hnh h thng qun l CTR l

d on c thnh phn ca cht thi trong hin ti v tng lai . Mt cch xc nh

n gin nht hin nay vn p dng l phng php mt phn t.

Trnh t tin hnh nh sau:

1. Mu CTR ban u c ly t khu vc ng.cu c khi lng khong 100-250kg. ng rc ti mt ni c lp ring bit, xo trn u bng cch

vun thnh ng hnh cn nhiu ln. Khi mu trn u ng nht chia

hnh cn lm 4 phn bng nhau.

2. Kt hp 2 phn cho nhau v tip tc trn u thnh 1 ng hnh cn. Tiptc thc hin bc trn cho n khi t c mu th nghim c khi lngkhong 20-30kg phn tch thnh phn.

3. Mu rc s c phn loi th cng, bng tay. Mi thnh phn s c tvo mi khay tng ng. Sau em cn cc khay v ghi khi lng ca

cc thnh phn. c s liu cc thnhphn chnh xc, cc mu thu thp

nn theo tng ma trong nm

b.Quy trnh th nghim (labortory procedure)

Vn c bn l kch c cc mu ln nh th no c gi ti phng th

nghim. Cu tr li i vi vn ny ph thuc vo cc quy trnh c s dng bi

phng th nghim. Mt quy trnh th nghim thng mi gm cc bc sau:

Mt phn vt cht ca mu c gi ti phng th nghim s c cn, lm kh,v c cn li xc nh hm lng m. Yu t gii hn g. on ny ca

quy trnh thng l ln ca l sy kh trong phng TN.

Mt phn vt cht kh c nghin thnh ht t 1/8 n 1/4 in. Mt phn vt cht t 1/8 n 1/4 in c nghin mn thnh bt, cng nh cng tt.

i vi nha do, phi thm vo kh trc khi nghin lm cho n gin hn.


35/36


Nhn chung, th nghim trong phng th nghim mt cch thc s c thc hintrn 0,5 n 3 gam vt cht c nghin mn, ph thuc vo loi th nghim, thit

b c th v quy trnh th nghim.

Nhng s thay i v quy trnh ny nh sau:

Huht cc phng th nghim khng c thit b nghin cc vt cht v c nhthy tinh v kim loi. Trong th nghim chy, vt cht ny b loi khi mu trc

khi nghin ri cn v ghi chp li nh l tro. i vi th nghim kim loi, cc vt

th kim loi c th b ct ra tng mnh bng tay hoc khoan to ra cc l nh

th nghim. Thy tinh v gm s thng b nghin.

Nhiu phng th nghim khng c cc thit b nghin mn v vy vic thc hincc th nghim trn vt cht tng i to, th.

Thm vo vic s dng cc phng php khc nhau chun b cht thi cho th

nghim, cc phng TN cng s dng cc phng php th nghim khc nhau. Vn

thc s khng phi l ln ca mu ln nh th no th c gi ti phng TN m l

i ng nhn s phng TN v ngoi thc a nn chia s nhim v l: lm gim cc mu

ti 1 hoc 2 gam

i vi cc mc ch thc hnh, khi lng ti a c gi ti phng th nghim nn l

khi lng m phng th nghim c chun b dn ra v trn ln trong vic chun b la chn vt cht c lm kh. Khi lng ti thiu nn l khi lng m phng th

nghim c chun b lm kh v nghin nh. Cc mu t hp lm th nghim ch

yu c tch ly trong cc ti nha ng rc ri ng hp vn chuyn.

Mt phng php khc l tch ly cc mu trong cc thng nha 5l c np y. Cc

thng nha th t hn nhiu so vi cc ti nha nhng c mt vi u im sau y:

Cc thng nha v np ca chng th d dng dn nhn v cc nhn thd dng c.

Cc np, chng ch c nhc ln ch khi vt cht c thm vo thng,ngn nga c tn tht m trong giai on ly mu hiu qu.

Vt cht ca mu c th c nn li trong cc thng nha nu n cy xung xung quanh ra bn trong.

c.Xem xt v s dng cc kt qu th nghim

Cc quy trnh, th tc th nghim khng hon chnh v cc li xy ra khi thc hin cc

quy trnh cng nh trong tnh ton v ghi chp cc kt qu l ph bin. Xem xt li


36/36


cc kt qu nhn c t mt phng TN thy chng c ngha hay khng l mt

vic rt quan trng.

Vic kim tra ny kh d dng i vi cht thi c tnh chy bi v nhiu ngi

c bit v cc c tnh gy chy ca CTR v cc vt cht thnh phn ca n. Nhn

bit cc kt qu th nghim b li i vi kim loi th kh khn hn nhiu so vi cccht hu c c hi. Sau y l cc hng dn ng dng nh gi tnh hp l,

ng n ca kt qu th nghim i vi cc c tnh gy chy trn c s kh:

cc kt qu trn c s kh i vi giy, cht thi sn vn, nha, g, v cc loibng v sinh c th tiu hy c nn gn vi kt qu ca cc vt cht k trn,

phi chp nhn s thay i ln hn trong cc kt qu n l i vi cht thi thcphm, dt/cao su/da, bi qung v cc cht t khc do s bin i v mt ha hc

ca nhng loi ny

trong s cc loi giy, ch c nhng loi vi t l giy bng cao nh l tp ch vcc th qung co nn c gi tr tro ln hn 10% mt cch ng k.

Phng th nghim nn t nguyn kim tra s tnh ton ny v lm nhc li th

nghim nu nh cc tnh ton khng phi l nguyn nhn ca vn . Nghin vn cc vt

cht khng u, dng khi ln nh cc ng g d nh trc khi chn lp

Documents

chuong 1_in